Because it's a cool show. Caroline Quentin (?) and Whatisname have great chemistry. It's got clever scripts and it's funny. It's got Giles as an Egotistical Jerk of a Master Magician (at least in the first episode). And it's British! Besides, Whatisname is adorable. Caroline Quentin (?) was on Whose line is it anyway? alot. She's very very talented.